[x3d-public] X3D minutes 11 FEB 2022: , X3D4 Particle Systems component review, adding enabled field to X3DParticleEmitterNode ?

[John Carlson]

I think it would be better to offer a transition from enabled to disabled
and back.   But perhaps that’s max speed and min speed?

But I agree that enabled is a good start, and adding a field for full on
and full off with no transition is a good idea.   One might think of scenes
where a door is shut.

I’m not sure if full on/full off matches physical reality.   I can think of
examples like bombs, volcanoes and dropping things though.

A combination of min/max speed and on/off would cover the cases I’m
thinking of.

John

On Fri, Feb 11, 2022 at 12:36 PM Brutzman, Donald (Don) (CIV) <
brutzman at nps.edu> wrote:

> Tweeted:
>
>
>
>    - X3D meeting minutes 11 FEB 2022: #X3D4 Architecture Particle Systems
>    component review.  Community question: is it OK to add 'enabled' field to
>    all emitter nodes, providing simpler animation control by authors and end
>    users?
>    - https://twitter.com/Web3DConsortium/status/1492205445120815105
>
>
>
> Request: if anyone has links or screenshots of Particle System models in
> X3D4, we are happy to share them publicly. Thanks in advance for all posts.
>
>
>
> all the best, Don
>
> --
>
> Don Brutzman  Naval Postgraduate School, Code USW/Br
> brutzman at nps.edu
>
> Watkins 270,  MOVES Institute, Monterey CA 93943-5000 USA
> +1.831.656.2149
>
> X3D graphics, virtual worlds, Navy robotics https://
> faculty.nps.edu/brutzman
>
>
>
> *From:* Brutzman, Donald (Don) (CIV) <brutzman at nps.edu>
> *Sent:* Friday, February 11, 2022 9:28 AM
> *To:* X3D Public Mailing List (x3d-public at web3d.org) <x3d-public at web3d.org
> >
> *Cc:* Brutzman, Donald (Don) (CIV) <brutzman at nps.edu>
> *Subject:* X3D minutes 11 FEB 2022: , X3D4 Particle Systems component
> review, adding enabled field to X3DParticleEmitterNode ?
>
>
>
> Attendees: Anita Havele, Vince Marchetti, Dick Puk, Don Brutzman.
> Regrets: Nicholas Polys, John Carlson.
>
>
>
>    1. Completed X3D4 Particle Systems component review.  All Mantis
>    issues updated and resolved.  Latest modifications highlighted via CSS with
>    corresponding Mantis issues documented using /title/ attributes.
>
>
>
>    - X3D4 Architecture, clause 37 Particle Systems component
>    -
>    https://www.web3d.org/specifications/X3Dv4Draft/ISO-IEC19775-1v4-CD1/Part01/components/particleSystems.html
>
>
>
>
>
> a. Improved issue notes, WindPhysicsModel:
>
>
>
>    - Mantis 464: 40.4.10 WindPhysicsModel - Question on Speed
>    - https://www.web3d.org/member-only/mantis/view.php?id=464
>    - Related issue: Mantis 768.  Deferred to X3D 4.1
>
>
>
> Likely pressure equation for future use will be based on difference
> between particle speed and wind speed.
>
> Note that the turbulence definition (regarding variability of wind
> direction) also needs improvement. For example, can highly turbulent wind
> stop or reverse direction?
>
>
>
>
>
> b. New deficiency noted: how do you turn off an emitter node?
>
>
>
> No /enabled/ field is present.  Possibly /speed/ might be zero, but then
> particle geometry would still be present and perhaps pulsing...  Possibly a
> Switch node might hide it, but then the browser writer likely just turns it
> off anyway to save computational resources, which is functionally
> equivalent to enabled FALSE.
>
>
>
> We discussed in some depth… Have raises an issue in Mantis, here posted
> publicly.  We seek comment, and decide (hopefully next week) whether it is
> something to be accomplished in X3D 4.0 or else deferred to X3D 4.1.
>
>
>
>
>
>    - Mantis 1380: ability to disable/enable X3DParticleEmitterNode
>    - https://www.web3d.org/member-only/mantis/view_all_bug_page.php
>
>
> Authors are unable to easily turn particle emitter nodes on or off.
>
> X3DParticleEmitterNode (and implementing nodes) need field:
>
>    SFBool [in out] enabled TRUE
>
> Implementation is simple for browsers. This field has no impact on legacy
> content.
>
> Current workarounds:
> * Possibly /speed/ might be zero, but then a particle would still be
> present and pulsing...
> * Possibly a Switch node might hide the emitter, but then the browser
> writer likely turns it off anyway to save computational resources, which is
> functionally equivalent to enabled FALSE.
>
>
>
> Of related note: X3DParticlePhysicsModelNode in this component does
> include an enabled field, for identical purposes.
>
>
>
>
>
> Vince discussed his Browser Review document noting X3D support, we hope to
> look at this draft further next week.
>
> No member-only information included on this page.
>
>
>
> Hope everybody has another great week.  Have fun with X3D!
>
>
>
> all the best, Don
>
> --
>
> Don Brutzman  Naval Postgraduate School, Code USW/Br
> brutzman at nps.edu
>
> Watkins 270,  MOVES Institute, Monterey CA 93943-5000 USA
> +1.831.656.2149
>
> X3D graphics, virtual worlds, Navy robotics https://
> faculty.nps.edu/brutzman
>
>
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